Based on their previous studies and preliminary data, the investigators hypothesize that during the initial stage of stromal differentiation, alphaSMA expression is regulated by the interaction between stromal cell integrins with the secreted extracellular matrix proteins laminin and fibronectin, and that during the second phase, a trophoblast factor, whose signal is mediated by cAMP, induces IGFBP-1 expression in decidualizing stromal fibroblasts, which in turn can downregulate alphaSMA. To investigate these hypotheses, they propose to characterize the mechanisms by which the integrin/ECM interactions could potentially regulate alphaSMA expression in isolated baboon stromal fibroblasts (Aim 1), identify the transcription factors that regulate IGFBP-1 gene expression in baboon decidual cells (Aim 2), and develop an in vitro implantation model to define the role of the baboon trophoblast in regulating the decidualization process (Aim 3).